1. Field of the Invention
The invention relates to a radio station which conducts radio communications in accordance with wireless LAN standard and an output prevention method which can be used in the radio station.
2. Description of the Related Art
Nowadays, a wireless LAN for realizing data communications by radio between stations or between a station and an external network becomes widely available.
Generally, a network of a wireless LAN is configured together with not only stations, but also access points each for playing a roll for relaying station-to-station radio communications and relaying radio communications between a station and an external network.
In each station in the wireless LAN, the same SSID (Service Set IDentifier or ESSID (Extended SSID)) as the SSID assigned to the access point is set as the connection data for conducting radio communications and the access point is determined, whereby it is made possible to access the access point. Since only the station in which the same SSID as that assigned to the access point is set has access to the access point (except for an exception), the SSID is also set from the aspect for use as an authentication function for connecting to the wireless LAN.
However, the following are defined for the access point according to the wireless LAN standard (IEEE 802.11): A beacon signal is transmitted for sending the SSID assigned to the access point to the surrounding stations at regular time intervals and upon reception of an inquiry request (probe request) from a station with the SSID set to “ANY,” a reply including the SSID of the access point (probe response) is returned. Since the SSID assigned to the access point can be determined from the beacon signal or the probe response, if the SSID is used as the authentication function, adequate security of the network cannot be provided; this is a problem.
Thus, in recent years, an access point of the specifications in which the SSID (connection data) is closed to the public (is not output) in such a manner that the SSID is not included in the beacon signal and that a reply not including the SSID of the access point is sent (or no reply is sent) in response to a connection request with the SSID set to “ANY” has been commercially available.
Such specifications would prevent the access point from transmitting the signal including the SSID (beacon signal, probe response) carelessly, so that the security of the network can be enhanced.
By the way, when various settings including the SSID (for example, WEP (Wired Equivalent Privacy) key, etc.,) are made in the station, if the station is provided with an easy-to-use user interface like a personal computer (PC), the user can easily make settings through the user interface.
However, with the station having no easy-to-use user interface as compared with the PC, such as a printer or a scanner, it is difficult for the user to make settings through the user interface. Some stations do not allow the user to make settings through a user interface. In most of such stations, data concerning settings is transferred to and from a different station, whereby the station is indirectly set (remotely set up) from the different station.
To thus transfer data to and from a different station, it is a common practice to conduct data communications by radio although data can also be transferred by data communications via a cable. However, at the time, it is feared that the SSID assigned to the access point may be determined from the data transferred to and from the different station by radio, and it is also feared that the radio data transfer may cause the security of the network to be degraded.
Proposed as an art for preventing degradation of the security caused by the radio data transfer is, for example, an art of transferring the data concerning the settings required for accomplishing data communications through an access point (set parameters) by a radio wave weaker than the usual radio wave between the station and the access point. (Refer to JP-A-2003-152735.) Accordingly, the reception zone of the data can be narrowed, so that the security of the network can be enhanced.
JP-A-2003-152735 is referred to as a related art.
As described above, in the wireless LAN, hitherto, various arts for enhancing the security of the network have been become commercially available and proposed. However, they are arts only for enhancing the security in the access point.
In the station in which the SSID of the access point is set, the SSID of the access point is recorded in memory, etc., of course, and therefore the possibility that a malicious user will know the SSID recorded in the station still remains.
As a specific example, the SSID of the access point to be accessed from the station is displayed on a display section of the station, whereby the SSID of the access point can be easily known. If the station has a network management function (SNMP (Simple Network Management Protocol) agent), it is also possible to send the SSID in response to an information request from a network management tool (SNMP manager).
Thus, in the wireless LAN, the security measures in the station are not sufficient as compared with those in the access point.